From: Chung-Lin Tang <cltang@codesourcery.com>
Date: Thu, 15 Mar 2012 10:04:12 +0000 (+0000)
Subject: backport: re PR rtl-optimization/52528 (combine bug (powerpc testcase))
X-Git-Tag: releases/gcc-4.6.4~640
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=791560ce0b352cad32d9fc82f25be6f567a14daf;p=thirdparty%2Fgcc.git

backport: re PR rtl-optimization/52528 (combine bug (powerpc testcase))

2012-03-15  Chung-Lin Tang  <cltang@codesourcery.com>

	Backport from mainline
	2012-03-10  Chung-Lin Tang  <cltang@codesourcery.com>

	PR rtl-optimization/52528
	* combine.c (can_combine_p): Add setting of subst_low_luid
	before call to expand_field_assignment().

From-SVN: r185425
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 33767fa4eb53..4ade03cc6375 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,12 @@
+2012-03-15  Chung-Lin Tang  <cltang@codesourcery.com>
+
+	Backport from mainline
+	2012-03-10  Chung-Lin Tang  <cltang@codesourcery.com>
+
+	PR rtl-optimization/52528
+	* combine.c (can_combine_p): Add setting of subst_low_luid
+	before call to expand_field_assignment().
+
 2012-03-12  John David Anglin  <dave.anglin@nrc-cnrc.gc.ca>
 
 	Backport from mainline
diff --git a/gcc/combine.c b/gcc/combine.c
index 74ec1e123fec..d1fdc96787c8 100644
--- a/gcc/combine.c
+++ b/gcc/combine.c
@@ -1788,6 +1788,10 @@ can_combine_p (rtx insn, rtx i3, rtx pred ATTRIBUTE_UNUSED,
   if (set == 0)
     return 0;
 
+  /* The simplification in expand_field_assignment may call back to
+     get_last_value, so set safe guard here.  */
+  subst_low_luid = DF_INSN_LUID (insn);
+
   set = expand_field_assignment (set);
   src = SET_SRC (set), dest = SET_DEST (set);